出典:Wikipedia
出典:『Wikipedia』 (2011/06/19 11:44 UTC 版)
A lock-in amplifier (also known as a phase-sensitive detector) is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment (S/N ratio can be -60 dB or even less). It is essentially a homodyne with an extremely low pass filter (making it very narrow band). Lock-in amplifiers use mixing, through a frequency mixer, to convert the signal's phase and amplitude to a DC—actually a time-varying low-frequency—voltage signal.
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to a get sliding door into position
wrench off the lock
the switchgear for the shutter
2開閉器
to wrench off a lock
to wrench off a lock
おりの境界
a loudspeaker that does not produce a magnetic field
a speaker who utters a sudden exclamation
補聴器.
the treble clef
a caisson
string-instruments